It is often desirable and frequently necessary to sample or remove a portion of tissue from humans and other animals, particularly in the diagnosis and treatment of patients with cancerous tumors, pre-malignant conditions, and other diseases or disorders.
Typically, in the case of cancer, particularly cancer of the breast, there is a great emphasis on early detection and diagnosis through the use of screening modalities, such as physical examination, and particularly mammography, which is capable of detecting very small abnormalities, often nonpalpable. When the physician establishes by means of a mammogram or other screening modality, such as ultrasound, that suspicious circumstances exist, a biopsy must be performed to capture tissue for a definitive diagnosis as to whether the suspicious lesion is cancerous. Biopsy may be done by an open or percutaneous technique. Open biopsy is a surgical procedure using a scalpel and involving direct vision of the target area, for removing the entire mass (excisional biopsy) or a part of the mass (incisional biopsy). Percutaneous biopsy, on the other hand, is usually done with a needle-like instrument through a relatively small incision, blindly or with the aid of an artificial imaging device, and may be either a fine needle aspiration (FNA) or a core biopsy. In FNA biopsy, individual cells or clusters of cells are obtained for cytologic examination and may be prepared such as in a Papanicolaou smear. In core biopsy, as the term suggests, a core or fragment of tissue is obtained for histologic examination which may be done via a frozen section or paraffin section.
The type of biopsy utilized depends in large part on circumstances present with respect to the patient, including the location of the lesion(s) within the body, and no single procedure is ideal for all cases. However, core biopsy is extremely useful in a number of conditions and is being used more frequently by the medical profession.
When an open surgical biopsy procedure is indicated, current practice dictates the use of lesion localization needles and devices, commonly referred to as “localization wires”, for use in localizing or marking non-palpable lesions and tumors within the body. These devices generally comprise a hypodermic needle or cannula which is inserted into the body under local anesthesia to the lesion or tissue of interest. The wire marker, or localization wire, is then passed through the cannula and extends through the lesion of interest so that the distal end thereof is anchored beyond the lesion. Thus, the lesion is marked for subsequent surgical procedures such as excision or biopsy. The anchoring procedure is typically accomplished by means of mechanical structure disposed at the distal end of the wire marker, such as a barb, hook, or the like, which is attached to surrounding tissue. After marking the lesion with the wire marker, the cannula is usually removed from the body, leaving the wire in place and extending from the body, for subsequent use by the surgeon during the biopsy procedure in identifying the lesion location. However, it often occurs that the barb or hook at the distal end of the wire marker attaches to something other than the tumor or lesion. For example, in the case of breast biopsies, the breast will typically be placed in compression during the imaging procedure in order to properly identify the location of the target lesion and place the localization wire. However, breast tissue is comprised of fibrous bands which, in compression, may be close to the target lesion and inadvertently engaged by the barb of the localization wire. Later, when the breast is released from compression prior to the surgical procedure, the fibrous bands will move away from the target lesion, and the distal end of the localization wire may thus move a substantial distance away from the target lesion.
It would be desirable, therefore, to develop a localization wire system and method wherein the distal end of the localization wire could be positively attached to the target lesion in order to minimize the possibility of migration of the distal end of the localization wire away from the target lesion between the imaging and surgical procedures.
In circumstances where a core biopsy procedure is indicated, various systems are available. Such systems are shown, for example, in U.S. Pat. No. 5,526,822 to Burbank et al, which discloses a probe having a laterally disposed tissue receiving port at the distal end thereof for acquiring relatively small tissue samples, and in U.S. Pat. No. 5,111,828 to Kornberg et al., which discloses a probe having an axially disposed tissue receiving port at the distal end thereof for acquiring relatively large intact tissue samples. Both of these patents are expressly incorporated by reference herein.
U.S. application Ser. No. 09/057,303 to Burbank et al., commonly assigned with the present application and expressly incorporated by reference herein, discloses still another core biopsy apparatus, which advantageously permits the acquisition of tissue samples which are larger in diameter than the diameter of the instrument lumen, thereby greatly increasing the chances of completely removing the target lesion and leaving “clean” margins thereabout.
As in the case of localization wires, there is some risk in using any of the foregoing devices that the distal end of the instrument will migrate away from the target lesion during the biopsy procedure, thereby reducing the likelihood of removing target tissue. Heretofore, in the case of core biopsy procedures, the risk of this occurrence is minimized by employing image guidance techniques during the entire tissue removal procedure. For example, in the case of the '822 Burbank et al. patent, a stereotactic imaging guidance system is typically utilized during the disclosed procedure. One disadvantage of this approach, however, is that the patient's breast must remain in compression during the entire procedure, with attendant discomfort and increased procedural difficulty, in order to properly utilize the imaging equipment. Furthermore, stereotactic imaging equipment or other suitable alternatives can cost as much as $400,000 or more and is not in the usual inventory of a typical community hospital. It would therefore be quite advantageous if a method and apparatus could be developed which would permit the uncoupling of the imaging environment from the procedural environment without undue risk that the active or cutting end of the core biopsy instrument would migrate away from the target lesion during the interval between the imaging procedure and the biopsy procedure.